Cantilevered screw assembly

ABSTRACT

A cantilevered screw assembly comprising an improved anchor system. In an exemplary embodiment, a support wall may be formed of a single casting with at least a portion of a bearing housing. An exemplary embodiment of a cantilevered screw assembly may also comprise at least one solid oil bearing to facilitate rotation of the screw.

This application is a continuation-in-part of U.S. application No. 14/818,751, filed Aug. 5, 2015, which is a continuation of U.S. application No. 13/667,313, filed Nov. 2, 2012, which claims the benefit of U.S. Provisional Application No. 61/555,863, filed Nov. 4, 2011, each of which is incorporated by reference in its entirety.

BACKGROUND AND SUMMARY OF THE INVENTION

Exemplary embodiments of the present invention relate generally to a cantilevered screw assembly. Examples of cantilevered screw assemblies may include, but are not limited to, augers, compactors, crushers, shredders, feeders, material handlers, bale breakers, briquetters, and autoclave sterilizers. Other applications of cantilevered screw assemblies are also possible.

There is a need to improve known cantilevered screw assemblies. Large scale cantilevered screw assemblies are in particular need of improvement due to the dynamics of such systems. Nevertheless, small scale cantilevered screw assemblies may have a similar need for improvement.

Known cantilevered screw assemblies have used grease-lubricated bearings. Such systems may provide a reservoir of grease that is supplied to the bearings. While effective, the reservoir of grease needs to be periodically refilled, which increases the necessary maintenance of the system. The associated downtime also limits the productivity of the system. In addition, replenishing the grease adds to the operational cost of the system. A further drawback is that the grease will eventually lead to oil drips or other oily messes. Thus, there are needs to improve the maintenance, operational costs, and environmental friendliness of cantilevered screw assemblies.

Additional needs exist to improve the stability, size, and load-bearing capacity of cantilevered screw assemblies. The screws of some known cantilevered screw assemblies have a tendency to shift in position or wobble during operation. The anchoring of known cantilevered screw assemblies may also limit load-bearing capacity. For instance, known assemblies may cantilever a screw to a load-bearing wall. The load-bearing wall may limit the size of the screw and the amount of material that can be processed. If the size of the screw is excessive, it may compromise the load-bearing wall. For example, it may lead to oil canning of the load-bearing wall. Oil canning may affect the operation of the screw as aforementioned, and it may eventually render the system inoperable.

Needs also exist to reduce the weight and manufacturing complexity of cantilevered screw assemblies. Some known cantilevered screw assemblies simply increase the girth of a load-bearing wall or include a series of bracing members in an attempt to increase the assemblies' load-bearing capacity. The assemblies of some known cantilevered screw assemblies also require many separate parts to be welded or otherwise assembled together to create the cantilevered screw assembly. This requires additional design and manufacturing complexity, including time, material, equipment, and labor resources to manufacture the assembly. Further, the additional fasteners, weld material, and other assembly devices add more weight to the assembly.

Exemplary embodiments may satisfy one or more of the aforementioned needs. One exemplary embodiment of a cantilevered screw assembly may include at least one bearing that includes solid oil. For example, one embodiment of a cantilevered screw assembly may include at least one bearing that is filled with solid oil. Such embodiments of a cantilevered screw assembly may offer numerous advantages including substantially decreased maintenance, lower operational costs, higher system efficiency, and improved environmental characteristics. It is estimated that the bearings of some exemplary embodiments may last at least two times longer between maintenance intervals as compared to a comparable cantilevered screw assembly that uses grease-lubricated bearings, which may significantly lower operational costs and raise operational efficiency. Moreover, oil leaks and drips may be substantially eliminated, drastically reducing the environmental impact.

Another exemplary embodiment of a cantilevered screw assembly includes an improved anchor system comprising at least one load-bearing wall. In particular, an exemplary embodiment may comprise a screw that is cantilevered to at least one wall. Examples of the improved anchor system may allow for a larger screw without compromising stability or the integrity of the load-bearing wall. Also, exemplary embodiments may enable more material to be processed by the cantilevered screw assembly with greater power and torque. Exemplary embodiments may further allow for reduced construction costs and assembly size when compared to assemblies requiring additional walls or other large assemblies for cantilevering the screw assembly.

Another exemplary embodiment of a cantilevered screw assembly includes a bearing housing and a wall comprised of a single casting. In particular, the wall may be cast with at least a portion of the bearing housing in an exemplary embodiment. For example, the bearing housing may comprise a body, a flared edge, a plurality of flanges, and/or a number of receptacles that are formed of a single casting with the support wall, thereby eliminating the need to manufacture and assemble these parts separately. In an exemplary embodiment, the single casting may reduce manufacturing and assembly costs when compared to assemblies requiring that these parts be manufactured separately and assembled. This may additionally reduce excess material such as weld material, fasteners, other assembly devices, or other excess material otherwise required to manufacture the assembly, which may reduce the weight of the assembly. Further, this may eliminate or lessen the need for increased girth of the walls or additional bracing members. This may also allow for increased strength and rigidity of a comparable or lesser weight assembly.

In addition to the novel features and advantages mentioned above, other benefits will be readily apparent from the following descriptions of the drawings and exemplary embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-section view of an exemplary embodiment of a cantilevered screw assembly.

FIG. 2 is a perspective view of the cantilevered screw assembly of FIG. 1.

FIG. 3 is a perspective view of an exemplary embodiment of a load-bearing wall assembly of the cantilevered screw assembly of FIG. 1.

FIG. 4 is a top plan view of the load-bearing wall assembly of FIG. 3.

FIG. 5 is a perspective view of the cantilevered screw assembly of FIG. 1. In this view, portions have been removed or rendered transparent for clarity.

FIG. 6 is a side elevation view of the cantilevered screw assembly of FIG. 5, wherein portions have been removed or rendered transparent for clarity.

FIG. 7 is a cross-section view of an exemplary embodiment of a cantilevered screw assembly, additionally indicating Detail A.

FIG. 8 is a view of Detail A of FIG. 7.

FIG. 9 is a cross-section view of the cantilevered screw assembly of FIG. 7.

FIG. 10 is a rear cross-section view of the cantilevered screw assembly of FIG. 7, where portions have been removed for clarity.

FIG. 11 is a perspective view of an exemplary embodiment of a cantilevered screw assembly, where portions have been removed for clarity.

FIG. 12 is a front perspective view of the cast wall assembly of FIG. 11.

FIG. 13 is a rear elevation view of the assembly of FIG. 11, additionally indicating section line A-A.

FIG. 14 is a view taken along section line A-A of FIG. 13.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENT(S)

Exemplary embodiments of the present invention are directed to a cantilevered screw assembly. FIGS. 1-6 show various views of one embodiment of a cantilevered screw assembly 10 comprising a screw 12, which has a shaft 14. In this example, the shaft 14 has a slight taper. Other types of cantilevered screw assemblies may also benefit from aspects of the present invention. For instance, some embodiments may not have a shaft with a taper, while other embodiments may have a shaft with a reverse taper. For embodiments that have a shaft with a taper or reverse taper, the degree of the taper or reverse taper may be selected to fit the application of the cantilevered screw assembly.

One aspect of an exemplary embodiment is the use of at least one solid oil bearing in association with shaft 14 to facilitate rotation. In the example of FIG. 1, a first solid oil bearing 20 and a second solid oil bearing 22 enable rotation of shaft 14. Other exemplary embodiments may include the use of more solid oil bearings.

An example of a solid oil bearing may have a cavity that is filled with solid oil. For example, solid oil bearing 20 has a cavity 24 that is filled with solid oil 26. Solid oil 26 may form adjacent or around the rolling elements of bearing 20, for example, to provide lubrication. Other bearing designs comprising solid oil are also possible.

An example of solid oil is comprised of oil in a polymer matrix or structure. In other examples, the supporting matrix or structure may be comprised of other types of plastic or other suitable material for retaining or reabsorbing the oil. In an exemplary embodiment, oil from the solid oil may provide lubrication substantially without dripping because the supporting material may have a porous structure that retains or reabsorbs the oil. The oil may coat contacting surfaces (e.g., the rolling elements), and the supporting structure is adapted to reabsorb any excess oil such that it is not expelled. Examples of solid oil are available from PhyMet, Inc. and SKF Group.

In another aspect, screw 12 is cantilevered to the walls of a multiple wall assembly 30. In this example, the multiple wall assembly 30 is comprised of at least a first wall 32 and a second wall 34 to which the screw 12 is cantilevered. This exemplary embodiment of multiple wall assembly 30 also includes a third wall 36 associated with shaft 14. Other embodiments may have more or less walls and/or may have a third wall that is not associated with the screw shaft. In an exemplary embodiment, the association of the screw with the multiple wall assembly may provide improved structural support for the cantilevered assembly as compared to a conventional single wall cantilevered assembly. Such an embodiment may increase the stability of the screw and also allow for a larger and more powerful screw that has the capacity to process more material.

Each wall is comprised of metal in this exemplary embodiment. In other embodiments, other materials having suitable structural properties may be used.

In this exemplary embodiment, first wall 32 is connected to second wall 34 by at least one reinforcement member. In combination with a multiple wall assembly, the use of an exemplary embodiment of at least one reinforcement member may further improve the stability of the screw and walls and also allow for an even larger and more powerful screw that is adapted to process more material. This embodiment includes a first reinforcement member 40, a second reinforcement member 42, a third reinforcement member 44, a fourth reinforcement member 46, a fifth reinforcement member 48, and a sixth reinforcement member 50 that are positioned around shaft 14 and the associated bearing assembly. In this example, the peripheries of first wall 32 and second wall 34 are also connected for additional reinforcement. Other embodiments may have less or more reinforcement members connecting the walls to achieve the desired reinforcement. Furthermore, in other exemplary embodiments, at least one reinforcement member may have any suitable position to connect a first wall to a second wall.

First reinforcement member 40, second reinforcement member 42, third reinforcement member 44, fourth reinforcement member 46, fifth reinforcement member 48, and sixth reinforcement member 50 are metal pipes in this exemplary embodiment. Other suitable reinforcement members may be used including, but not limited to, metal bars and other hollow or solid metal members. In addition, other suitable materials besides metal may be used for certain applications.

The bearing assembly may include a bearing housing adapted to house at least one bearing. In this embodiment, the bearing assembly includes a bearing housing 60 for housing bearing 20 and bearing 22. The bearing housing 60 extends between first wall 32 and second wall 34 in this example. Bearing housing 60 may serve as further reinforcement in this manner. Such as seen in FIGS. 5 and 6, an example of a bearing housing 60 may include at least one flared edge 62 and at least one flange 64 to assist with stabilization and/or securement to one or more walls (in this example, wall 32). In addition, an example of flared edge 62 may define at least one receptacle 66 to assist with securing a reinforcement member. At the same time, second wall 34 further supports bearing housing 60. Such an embodiment may increase the stability of screw 12 and the walls, and it may also allow for a larger and more powerful screw with the capacity to process more material.

With respect to the example in FIG. 1, solid oil bearing 20 is substantially aligned with first wall 32, and solid oil bearing 22 is substantially aligned with second wall 34. In other exemplary embodiments, a bearing housing may extend out further beyond the first wall (in a distal direction) and/or the second wall (in a proximal direction), such that a bearing is not aligned with a respective wall. An example of such an embodiment may increase the stability and strength characteristics of the screw. Also, in some exemplary embodiments, one or more bearings may be situated between the first wall and the second wall (i.e., not aligned with either wall).

As aforementioned, bearing housing 60 extends about solid oil bearing 20 and solid oil bearing 22 in this example. In other exemplary embodiments, a bearing housing may house fewer or more bearings. Furthermore, the bearings are not limited to solid oil bearings in this embodiment. For instance, although solid oil bearings may be preferred, this embodiment may include grease-lubricated bearings or other types of bearings.

Referring to FIGS. 1 and 2, a drive chain assembly 70 may be situated outside of second wall 34 (i.e., on the proximal side of second wall 34). More particularly, drive chain assembly 70 is situated between second wall 34 and third wall 36 in this example. However, in some other exemplary embodiments, a drive chain assembly may be situated within a second wall or in another suitable position for facilitating rotation of the screw 12. In the example shown, drive chain assembly 70 is comprised of a first sprocket 72 and a second sprocket 74. In FIGS. 2, 5, and 6, sprocket 72 is shown as being transparent in order to show other exemplary features. Sprocket 74 is also transparent in FIG. 6 for clarity. Likewise, second wall 34 has been removed in FIGS. 5 and 6 for clarity. In other exemplary embodiments, other types of drive chain assemblies or other types of drive mechanisms may be used to facilitate rotation of the screw.

FIGS. 7-10 show various views of another exemplary embodiment of a cantilevered screw assembly 110. Many aspects of this exemplary embodiment are similar to the previous embodiment. It should be appreciated that similar features may be structured similarly, operate similarly, and/or have the same function unless otherwise indicated by the drawings or this specification. For example without limitation, a screw 112, which has a shaft 114, is rotatably mounted by the use of at least a first solid oil bearing 120 and a second solid oil bearing 122 that are housed in a bearing assembly comprising a bearing housing 160. In this example, the bearing housing 160 may extend through a first wall 132. The bearing housing 160 may comprise a body 161 that houses the bearings. The bearing housing 160 may further comprise at least one flared edge 162 in association with at least one flange 164, wherein at least one flared edge 162 and at least one flange 164 extend from body 161. In one exemplary embodiment, the bearing housing may be secured or reinforced in part by the use of a series of receptacles 166 adapted to house a series of reinforcement members. Additionally, in an exemplary embodiment, a drive chain assembly 170, a first sprocket 172, and a second sprocket 174 may likewise power the rotation of the cantilevered screw assembly 110.

In the present exemplary embodiment, screw 112 is cantilevered to a wall of a multiple wall assembly 130. In this exemplary embodiment, the multiple wall assembly 130 is comprised of the first wall 132 to which the bearings are mounted and the screw 112 is cantilevered. This exemplary embodiment of multiple wall assembly 130 also includes an anchor wall 136 associated with shaft 114. In an exemplary embodiment, the association of the screw with the multiple wall assembly may provide improved structural support for the cantilevered assembly as compared to known cantilevered assemblies. Such an embodiment may increase the stability of the screw and also allow for a larger and more powerful screw that has the capacity to process more material.

In this exemplary embodiment of the multiple wall assembly 130, the first wall 132 is connected to anchoring wall 136. The first wall 132 may be framed by a channel 102, which may extend from the first wall 132 to the anchoring wall 136. In this example, first wall 132 and at least a portion of bearing housing 160 may be formed as a one-piece unit. More particularly, in a preferred exemplary embodiment, first wall 132 and at least a portion of bearing housing 160 (e.g., at least a portion of body 161, flared edge 162, and/or flange 164) and/or channel 102 may be formed of a single casting. In another example, the bearing assembly may be fixed to the first wall 132 in part by at least one reinforcement member and/or at least one reinforcement member may reinforce first wall 132 and/or bearing housing 160. Alone or in combination with a multiple wall assembly, the use of an exemplary embodiment of a single casting with or without at least one reinforcement member may further improve the stability of the screw and wall(s) and also allow for an even larger and more powerful screw that is adapted to process more material.

The bearing housing 160 may extend beyond first wall 132 and between first wall 132 and anchoring wall 136 in this example. Bearing housing 160 may serve as further reinforcement in this manner. In this exemplary embodiment, first solid oil bearing 120 and second solid oil bearing 122 are respectively situated on opposite sides of first wall 132. With respect to the example in FIG. 7, the bearing housing may extend out further beyond the first wall 132 (in a distal direction), such that first solid oil bearing 120 is not aligned with a respective wall but is located beyond the first wall 132 (i.e., on a distal side of first wall 132). The second solid oil bearing 122 may be located between the first wall 132 and the anchoring wall 136 in this example. In other words, the first wall 132 may be situated or aligned between the first solid oil bearing 120 and the second solid oil bearing 122. Such an embodiment may permit a larger screw 112. For example, the flight of screw 112 may be configured to extend over the bearing housing 160 such as shown in FIG. 7, thereby allowing for a larger screw 112 as well as preventing material from collecting around bearing housing 160 where it may not otherwise be accessible by the screw 112. In other exemplary embodiments, however, at least one bearing may be aligned with a wall. An example of such an embodiment may also increase the stability and strength characteristics of the screw.

Referring to FIG. 10, the anchoring wall 136 has been removed for clarity. The drive chain assembly 170 may be situated outside of first wall 132 (i.e., on the proximal side of first wall 132). More particularly, drive chain assembly 170 is situated between first wall 132 and anchoring wall 136 in this example. However, in some other exemplary embodiments, a drive chain assembly may be situated in another suitable position for facilitating rotation of the screw 112. Also, in other exemplary embodiments, other types of drive chain assemblies or other types of drive mechanisms may be used to facilitate rotation of the screw.

As mentioned above, in preferred exemplary embodiments of the present invention, at least a portion of the bearing housing 160 may be integrally formed with the first wall 132, such as being formed of a single casting. In another exemplary embodiment, the bearing housing 160 may be separately formed from the first wall 132. For example, the bearing housing 160 may be secured to the first wall by welding, press-fit, fasteners, or any other attachment means.

FIGS. 11-14 show various views of another exemplary embodiment of a cantilevered screw assembly 210 featuring a cast wall assembly, where the screw and other portions are not shown for clarity. Many aspects of this exemplary embodiment are similar to the previous embodiments. It should be appreciated that similar features may be structured similarly, operate similarly, and/or have the same function unless otherwise indicated by the drawings or this specification. For example without limitation, a bearing assembly may comprise a bearing housing 260, which is associated with a first wall 232 and comprises at least one flared edge 262 and at least one flange 264 and may be adapted to be reinforced such as by the use of a series of receptacles adapted to house a series of reinforcement members. Additionally, the assembly may be associated with at least one wall of a multiple wall assembly 230. For example, the multiple wall assembly 230 may be comprised of the first wall 232, to which the screw is cantilevered and the bearings are mounted. Though not shown in the present figures, the multiple wall assembly may also include an anchor wall associated with the shaft.

In the present exemplary embodiment, a first wall assembly 200 may be comprised of the first wall 232, bearing housing 260, at least one flared edge 262, and/or at least one flange 264. An exemplary embodiment of first wall assembly 200 may also include a second flared edge 208. The second flared edge 208 may be located, sized, and adapted to allow the motor for a drive chain assembly (e.g., 170 comprising at least one sprocket (e.g., 174) and related components) to pass through and be mounted thereto. In a preferred embodiment, the first wall assembly 200 may be comprised of a single casting. A single casting advantageously strengthens the assembly and facilitates improved distribution of the forces associated with cantilevering the screw assembly, which may permit the assembly in one exemplary embodiment to be cantilevered without the need for bulky reinforcement members or otherwise larger components to handle the associated forces. In addition, a cast wall assembly may decrease assembly costs and increase manufacturing efficiency.

In an exemplary embodiment, this single casting may also reduce the weight of bearing housing 260 by removing otherwise required weld material, fasteners, or other assembly devices. This may likewise increase the strength and rigidity per weight of first wall assembly 200, thereby increasing the stability of the screw. This may also reduce the manufacturing and assembly complexity required by reducing the number of parts required to be manufactured and assembled. Alternatively, the bearing housing 260 may be separately formed from the first wall 232 in some exemplary embodiments. In such embodiments, the bearing housing 260 may be secured to the first wall by welding, press-fit, fasteners, or any other attachment means.

The flared edge 262 and the at least one flange 264 may extend further across first wall 232 (i.e., may be larger) in the present embodiment compared to previous embodiments described herein. Such an embodiment may allow for improved distribution of forces caused by the screw, which may promote increased stability and strength of first wall 232. More particularly, an embodiment comprised of a cast wall assembly may allow for the flared edge 262 and the at least one flange 264 to extend further across first wall 232 as compared to previous embodiments of a similar weight that are not comprised of a cast wall assembly, thereby increasing strength and stability per weight.

The first wall 232 may be framed by a channel 202, which may also be included in the single casting in some embodiments to further enhance strength and stability. The channel 202 may extend from the first wall 232 to the anchoring wall. As needed, in view of channel 202, the upper and lower portions of the flared edge 262 may comprise flat surfaces 206 to permit the flared edge 262 to fit on the first wall 232. However, an example of the channel 202 may comprise at least one arched section 204 configured to accommodate a larger flared edge 262 without a corresponding flat surface 206.

An example of the first wall assembly 200 may comprise a series of receptacles 266, which may function similarly to the receptacles 166, though they may be of different size and location. The receptacles 266 may be sized and located to receive reinforcement members. As a result of casting, however, an exemplary embodiment may not require additional reinforcement members. In such other embodiments, the receptacles 266 may be more accurately described as apertures, which may likewise be located between each of the at least one flange 264. For example, the apertures 266 may be utilized without reinforcement members and may serve to reduce the amount of material and thus the weight of the first wall assembly 200, while still providing sufficient stability and strength for particular applications.

Due to the aforementioned benefits, the exemplary embodiments of a cantilevered screw assembly are particularly useful for processing waste materials. However, exemplary embodiments of a cantilevered screw assembly may also serve other purposes not limited to the processing of waste materials.

Any embodiment of the present invention may include any of the optional or preferred features of the other embodiments of the present invention. The exemplary embodiments herein disclosed are not intended to be exhaustive or to unnecessarily limit the scope of the invention. The exemplary embodiments were chosen and described in order to explain some of the principles of the present invention so that others skilled in the art may practice the invention. Having shown and described exemplary embodiments of the present invention, those skilled in the art will realize that many variations and modifications may be made to the described invention. Many of those variations and modifications will provide the same result and fall within the spirit of the claimed invention. It is the intention, therefore, to limit the invention only as indicated by the scope of the claims. 

What is claimed is:
 1. A screw assembly comprising: a screw housing comprising a first wall; a screw situated in and cantilevered to said first wall; and a bearing assembly secured to said first wall of said screw housing and adapted to facilitate rotation of said screw relative to said first wall, said bearing assembly comprising a bearing housing that houses at least one solid oil bearing comprising oil in a polymer structure that is adapted to retain or reabsorb said oil; wherein said first wall and at least a portion of said bearing housing are formed of a single casting.
 2. The screw assembly of claim 1 wherein each said solid oil bearing comprises a cavity filled with said oil.
 3. The screw assembly of claim 1 wherein said screw comprises a shaft in association with said at least one solid oil bearing.
 4. The screw assembly of claim 1 wherein said bearing housing comprises: a body; and at least one flared edge extending from said body; wherein at least a portion of said body and said at least one flared edge are formed of said single casting with said first wall.
 5. The screw assembly of claim 1 wherein said at least one solid oil bearing comprises a first solid oil bearing and a second solid oil bearing.
 6. The screw assembly of claim 5 wherein said first wall is adjacent to and spaced apart from a second wall of said screw housing.
 7. The screw assembly of claim 6 wherein said first and second solid oil bearing are respectively situated on opposite sides of said first wall such that said first solid oil bearing is situated on a distal side of said first wall and said second solid oil bearing is situated between said first wall and said second wall.
 8. The screw assembly of claim 6 further comprising a drive chain assembly situated between said first and second wall; wherein said drive chain assembly is adapted to facilitate rotation of said screw.
 9. The screw assembly of claim 1 wherein said bearing housing extends through said first wall.
 10. The screw assembly of claim 9 wherein a flight of said screw extends over said bearing housing.
 11. A screw assembly comprising: a multiple wall assembly comprising a first and second wall that are adjacent to each other and spaced apart; a screw cantilevered to at least said first wall of said multiple wall assembly; and a bearing assembly secured to said first wall of said multiple wall assembly, said bearing assembly adapted to facilitate rotation of said screw relative to said first wall, said bearing assembly comprising a bearing housing that houses at least one solid oil bearing comprising oil in a polymer structure that is adapted to retain or reabsorb said oil; wherein said first wall and at least a portion of said bearing housing are formed of a single casting.
 12. The screw assembly of claim 11 further comprising at least one reinforcement member connecting said bearing assembly to said second wall of said multiple wall assembly.
 13. The screw assembly of claim 11 wherein said screw comprises a shaft associated with said multiple wall assembly.
 14. The screw assembly of claim 11 wherein said bearing housing comprises: a body; and at least one flared edge extending from said body; wherein at least a portion of said body and said at least one flared edge are formed of said single casting with said first wall.
 15. The screw assembly of claim 11 further comprising a drive chain assembly situated between said first and second wall of said multiple wall assembly; wherein said drive chain assembly is adapted to facilitate rotation of said screw.
 16. A screw assembly comprising: a multiple wall assembly comprising a first and second wall that are adjacent to each other and spaced apart; a screw cantilevered to at least said first wall of said multiple wall assembly; and a bearing assembly secured to said multiple wall assembly and adapted to facilitate rotation of said screw relative to said multiple wall assembly, said bearing assembly comprising a bearing housing that houses a first and second solid oil bearing respectively comprising oil in a polymer structure that is adapted to retain or reabsorb said oil such that said first wall of said multiple wall assembly is aligned between said first and second soil oil bearing; wherein said first wall and at least a portion of said bearing housing are formed of a single casting.
 17. The screw assembly of claim 16 further comprising a plurality of reinforcement members connecting said first wall to said second wall such that said reinforcement members are positioned around a shaft of the screw.
 18. The screw assembly of claim 16 wherein: said bearing housing extends through said first wall; and a flight of said screw extends over said bearing housing.
 19. The screw assembly of claim 16 wherein said bearing housing comprises: a body; and at least one flared edge extending from said body; wherein at least a portion of said body and said at least one flared edge are formed of said single casting with said first wall.
 20. The screw assembly of claim 16 further comprising a drive chain assembly situated between said first and second wall; wherein said drive chain assembly is adapted to facilitate rotation of said screw. 